Background: Facial seborrheic dermatitis (FSD) is a chronic relapsing skin disease caused by multifactorial factors. Long-term or frequent topical corticosteroid treatment may lead to adverse effects.

Aims: To determine the long-term efficacy of a trial moisturizer containing 4-t-butylcyclohexanol and licochalcone A as an adjunctive treatment and its effectiveness in extending the disease-free period in FSD patients.

Patients/Methods: Twenty patients with FSD aged ≥ 18 years were enrolled. They individually received a trial moisturizer to apply to their faces twice daily for 20 weeks. Clinical assessment by a physician, patient assessments, and bioengineering measurements were performed periodically.

Results: Clinical severity assessment showed a significant improvement after 1 to 2 weeks of treatment compared with the baseline. The trial moisturizer promoted skin hydration and reduced transepidermal water loss. The number of patients with disease exacerbations and frequency of relapses significantly decreased after the first week and during the remainder of the study period. No participants needed rescue by topical corticosteroid therapy.

Conclusion: The moisturizer containing 4-t-butylcyclohexanol and licochalcone A showed excellent efficacy without unwanted effects. It is endorsed for use as an adjunctive treatment or maintenance therapy to control the relapse of mild to moderate FSD.